Safety valve



. Feb. 16, `1954 v. w. FARRIS 2,669,252

SAFETY VALVE Filed Feb. 21. 19 5O f 2 Sheets-Sheet l //a Y 4 5 47 F/a/ s63 6 5 .s/ 33 5a l.; 30

a 64l '59 5 -g 26 /4 121/ l Jo 5, 49 f 2f 2 /a MSNM H, m

Patented Feb. 1,6, 1954 zatazsz UNITED STATES lPATENT OFFICE 2,669,252ysAFE'rYYvALvE c victor Wallace Farris, Tenany, N. J. ApplicationFebruary' 21, 1,950, serial No. 145,456

vafter the initial popping of the valve, vthe attainment of maximumopening, generally accepted,

for maximum efficiency, to be equal to Where D is the diameter of thedischarge orifice, depended upon this same pressure. As a matter offact, with elastic fluids, the pressure. must reach about 3% over theset pressure before can be attained, and in the case of inelasticfluids. this over-pressure must reach about 40%. Now, the pressureexerted against the valve disc is partially a function of the shape ofthe nozzle,vr a tapered nozzle generally being employed to aid inIreaching the necessary overpressures. But tapered nozzles reducecapacity, thereby increasing the time elapsing before reaching maximumcapacity. This lag is detrimental for many applications, and oftennecessitates the use of larger and more costly valves in an effort toVcompensate therefor.

. The closing of such valves has heretofore been dependent solely uponthe reduction of the pressure exerted by the fluid being controlled, thespeed of such closing and thepressure 4at which .the valve finallyclosed being a function of the position of the blow-downv ring. This hasthe disadvantage that the difference between 'the openprovide a safetyvalve in which the discharging iiuid is utilized' to aid `the openingofthe valve, thereby attaining maximum lift and capacity in minimum time..f nIt is still another object of the present invention to provide avalve in which a straight, rather 8 Claims. (Cl.l 137-472) than atapered, nozzle may be yemployed so as to increase capacity, capacitywithout sacricing lift.

and attain this increased "It is a further object of the presentinvention to provide a safety valve in which the discharging 'fluid isalso utilized to aid the closing of the valve, thereby giving greatercontrol over the vblow-down point than has heretofore been possible, andeliminating chatter.

I It is a still further object of the present invention toprovide asafety Valve the construction and mode of operation of which are such asto enable the use of a smaller valve for a given Vinstallation than hasheretofore been required.

It is a further object of the present invention to provide a valve inwhich the effects of spring hysteresis are eliminated.

These, and other objects of the present invention, which will becomemore apparent as the detailed description thereof progresses, areattained, broadly, in the following manner.

i' In a preferred form, the present invention contemplates the provisionof a valve body having lmain and auxiliary chambers, the main chamber'including means providing communication with the interior thereof. Avalve disc cooperates with this means to control the communicationtherethrough, the pressure at which the disc operates being adjustable.A pressure-responsive member isv disposed in the auxiliary chamber todivide vtheY same into first and second compartments, saidpressure-responsive member being coupled to the above-mentioned valvedisc. Additional means provide communication between said rst andsecondv compartments and said main chamb er, preferably, at a pointlocated closely adjacent said valve disc so as to be exposed to themaximum velocity of the discharging fluid. The communication between thefirst compartment and the' main chamber is controlled by another valve,disc, this discbeing operable by effective connection with the firstvalve disc during the operation of the latter. The first and secondcompartments of the auxiliary chamber additionally communicate with themain chamber, the additional communication between the first compartmentand the mhain chamber being controlled by'a third valve disc, in turn,coupled to, and operated in unison with, the second valve disc. Finally,the additional communication between the second compartment and the mainchamber is provided with a needle valve to adjustably restrict the'ori`ce thereof.

When the pressure against the first valvefdisc reaches a. predeterminedvalue, this disc starts to open, enabling the iiuid being controlled tocommence discharging through the main chember. At the same time, thesecond and third Valve discs open, whereby one portion of the discharging fluid enters the iirst compartment of the auxiliary chamber toact on the pressure-responsive member therein in a direction to aid theopening of the first valve disc. Another portion or" the dischargingduid is by-passed. through the third valve disc back to the main chamberso as to prevent this fluid from entering the second compartment of theauxiliary chamber and counteracting the aiding action of the fluid inthe rst compartment. Thus, the first valve disc is quickly brought toits maximum opening with the aid of the fluid controlled thereby. y

As the pressure of said uid drops, the first valve disc commences toclose. During this -closing movement, the second and third valve discsalso close, cutting off .the communication between the first compartmentof the auxiliary chamber and the main chamber, and the `by-pass of thesecond compartment to the Amain chamber. However, inasmuch as the firstvalve disc is still partially open, aportion of the fluid whichcontinues to Adischarge isconveyed to the second compartment of theauxiliary chamber. This fluid builds up pressure against the abovereferred to pressure-responsive member ,in a .direction to aid theclosing of the rfirst valve disc, the rate at which this pressure buildsup depending on the 'setting of the needle valve controlling thevorifice of .the previously mentioned additional communication betweenthe second `compartment and the main chamber. vIf this `orifice issmall, Athe pressure builds .up rapidly and `the first valve disc closesat a pressure `near that at which it opened. On the other hand, Vif thisorice is large, much of the fluid is .by-passedback to the main chamberand the pressure Lagainst the pressure-responsive member buildsupslowly. In this case, the first Valve disc closes slowly, .and thefinal pressure at which it .becomes completely closed is controlled,primarily, -by the position of the conventional blow-,down ring of thede- Y. Thus, the discharging fluid is utilized to vice. aid in lclosingras well as vopening the first valve disc, and the disadvantages ofexisting devices, above set forth, are eliminated.

In the accompanying specification there ,shall be described, and in theannexed drawing shown,

`an illustrative `embodiment .of safety valves. It is, however, to 'be.clearly understood .that the `inesent invention is not t0 be limited.to the exact details herein shown and `described for .purposes ofillustration only, inasmuch as changes therein may be made without the4exercise of .invention and within the true spirit 4and scope of 'theclaims hereto appended.

Referring now more i-n detail tothe :aforesaid illustrative embodimentof the present invention,

:with vparticular Areference to .the ,drawingsillus- `.tra-ting thesame, the numeral ID generally indicates a safety valve including amain'body Il,

-a bonnet I2, and :an auxiliary body -I3 secured `between said main bodyand said bonnet.

The'main body II is provided with a main or I6. The bonnet yI2 isYprovided with a an auxiliary chamber I9 divided by a peripherallymounted flexible diaphragm .2.0 into first Vand second lcompartments2Iand 122. While thedia- 4 phragm 20 is, preferably, made of metal, itmay also be made of suitable rubber or the like.

Threadedly engaged in the inlet port I5, and extending into the mainchamber I4 of the body II, is a high velocity nozzle 23 at the inner endof which there is formed a valve seat 24, and cooperable with the seat24 is a disc 25 carried by a disc-holding member 26.

The disc-holding member 25 is, in turn, coupled to a vvalve stem 21which rises upwardly through a sleeve 28 formed with said disc-holdingmember, said sleeve Ibeing slidably mounted in a cylin- .der 29supported in spaced axial relationship with .the nozzle 23 from a baffle3i) secured at the periphery thereof between the bodies II and I3. .Thelstem -2'1' passes through packing nuts 3I and 32 in the walls 33 .and34 of the auxiliary body I3, and through a central opening in thediaphragm 23, and extends into the spring chamber I1 of the bonnet 12,said stem having a threaded portion .35 engaging discs 3.3 and 31contacting vopposite sides of said diaphragm 20 whereby said diaphragmand said stem can move aS a unit.

Near its upper end, the stern 21 is slidably mounted in aspring-adjusting screw v38 engaged in the bonnet i2, said screw bearing.against .a button 39 which is loosely mounted on the stem 21 and which,in turn, bears against the upper end of a coil spring le the :lower end.of which abuts another button 4i which is fastened on the stem 21. Thescrew-3:8 is adapted to be locked in position by a nut 42. Threadedlyengaged on ,the outer end of the stem 2, and locked in position thereonbya cotter lpin 43, is :a stem testnut iid, vtheunderside of said nutbeing engaged lby a cam fixed upon a stud shaft 43 journalled in the capI3, said shaft ,also having fixed thereon a test lever 41.

Surrounding the disc 25 and formed on the disc-holding member 2B, "is adepending flan-ge `48,' -said flange having `an interior surface 43which ares outwardly from a at, secondary disc area presented by the4under surface of the disc-holding member '26, in a direction oppositetoffiuid fiow through the vnozzle 23.

,'Threadedly engaged yadjacent the seat end of the nozzle 23 Yis -ablow-down `ring 5I adapted, after suitable adjustment, to be fixed inposition b y a lockinggscrew 52 carried in the main body II Aandengageable with serrations '53 formed about said ring.

The auxiliarybody I3 is provided with a'bore 54 communicating betweenthe first compartment 2l thereof `and a sub-chamber 55 lformed therein,Vsaid sub-chamber communicating ,in one direction, through a port 5E anda bore 51, with the second compartment 22 of said ,auxiliary'body andinthe opposite direction, through abore 58, with a conduit 59. Saidconduit 59 enters 4the lmain 4body LI in the region of the junction ofthe inlet and Outlet ports I5 and i5, and projects into the main chamberI4, terminating adjacent the disc 25 and seat 24 so as to lbe exposedYto fluid passed by said disc in the region of the maximum velocitythereof.

V'lhe' 'sub-chamber 55 also communicates, Athrough .borefiL with anadditional sub-,chamher 5I, the latter `communicating in onedirecftio'n, V'tl'lrough ,a l:Dort 5,2 and the bore '51, with thesecondcompartment 22 of the auxiliary body i3, `and ,in the opposite'direction, through a bore '53, 'with a conduit 54. The latter enters theoutlet port .I6 of the main body I.I and terminates fa 4,region remotefromthe disc 25 .and seat 24.,

preferably, facing away from the latter members so as to set up suctionin the conduit as discharging fluid flows past the same.

The bore 54 is provided with a sleeve lining 65, the communicationbetween the first compartment 2| of the auxiliary body I3 and thesub-chamber 55 afforded thereby being controlled by a second valvediscBImounted on a stem or push-rod 61. The latter is grooved, as at 68, andhas its inner end slidably supported in a bearing 69 formed on the wall33 of the auxiliary body I3.

An extension of the second disc 66 isslidably mounted in the bore 60,said extension being grooved, asat 1I, to provide the rear communicationbetween the sub-chambers 55 and 6I, said communication being controlledby a third valve disc 12 carried at the outer end of the push-rod Thus,the second and third discs 65 and 12 are coupled for simultaneousoperation. The size of the port 62 is controlled by a needle, valve 13threadedly engaged in the wall '34 of the auxiliary body I3, and theouter end of the sub-chamber 6I is closed by a plug 14.

Finally, a cam nut 15 engages the threaded vportion35 of the stem 21adjacent the 'inner end oi" the push-rod 61, the push-rod beingmaintained in a position to normally close the discs 66 and 12 by meansof an expansion spring 16; The arrangement is such that movement of thelstem 21 brings the cam 15 into engagement with the push-rod tosimultaneously operate the second and third discs 66 and 12 against thevaction of the spring 16.

This` completes the description of the afore-v said illustrativeembodiment of the present invention and the mode of operation thereofmay be summarized as follows:y

. As the pressure exerted by the uid being controlled against the firstdisc 25 reaches a predetermined value, depending on the adjustment ofthe spring 40, said disc opens. The fluid commences to discharge throughthe chamber I4 and the outlet port I5. Opening of the disc 25 causes thecam 15 to engage, at a predetermined time, the push-rod 61 and slide thesame so as to open the second and third discs 66 and 12 againsttheaction of the spring 16.

A portion of the discharging iiuid enters the conduit 59 withconsiderable velocity and reaches the sub-chamber 55. It here divides,major portions entering the first compartment 2'I through the groove 68,and the sub-chamber 6I vthrough the groove 1I. A minor portion entersthe second compartment 22 through the ports 56 and 51. The portionentering the subchamber 6I is returned to `the main body of dischargingiiuid through the port 63 and conduit '64., A difference in fluidpressure is thus established between the compartments 2| and 22, withthe greater pressure in the compartment 2I. This pressure is exertedagainst the diaphragm and aids the pressure against the first disc tohelp the latter quickly attain maximum opening.

vAs the pressure of the fluid being controlled is relieved, the firstdisc 25 commences to close under the action of the spring 40. At apredetermined time during the closing of this disc, `the cam 15 becomesdisengaged from the pushrod 61 and-the discs 66 and 12 close under theaction of the spring 1B.

However, inasmuch as the disc 25 is. still partially open, uid continuesto discharge and enter the sub-chamber 55 through theconduit 59.

6 From here, it enters the ports 55 and 51, a portion flowing to thesecond compartment 22 and a portion flowing through the port 62 to thesubchamber 6I. From the latter, the fluid returns to the main streamthrough the port 63 and conduit 64.

The amount of fluid passing the port 62 depends on the setting of theneedle valve 13. If the orifice is large, considerable uid 'by-passesthe compartment 22 and pressure in the latter builds up slowly. On theother hand, if the orice is small, not much uid can pass there- -throughand the pressure in the compartment 22 builds up rapidly. In eitherevent, this pressure is exerted against the diaphragm 22 to aid ythespring 4i) in closing the disc 25. It Will be vention. It will be seenfrom all of the foregoling that a safety valve has been provided inwhich the disadvantages of prior devices, set forth in earlier portionsof this specification, are eliminated. It will further be seen that aAvalve has been provided in which the fluid controlled thereby is causedto aid both in the opening and closing thereof. Finally, it will beappreciated that with the valve of the present invention, it becomespossible to employ smaller Vvalves for a given installation than hashereto:- .fore been the case.

Other objects and advantages of the present invention will readily occurto those skilled in the art to which the same relates.

What is claimed is:

l. The combination of a body provided with main and auxiliary chambers;means providing communication with the interior of said main chamber; afirst spring-pressed disc normally closing said communication; apressure-responsive member disposed in said auxiliary chamber, andcoupled to said first disc; means providing communication between saidmain and auxiliary chambers; a second spring-pressed disc normallyclosing said last-named communication; a cam coupled to said first disc;and a push-rod extending from said second disc to a point adjacent saidcam; said cam engaging said push-rod during the operation of said rstdisc to actuate said second disc.

2. The combination of a body provided with main and auxiliary chambers;means providing communication with the interior of said main chamber; aiirst valve means controlling said communication; means maintaining said:Ilrst valve means normally closed; a diaphragm 'peripherally mounted insaid 'auxiliary chamber, and dividing the same'into first and secondcompartments; said diaphragm being coupled at the center thereof to saidfirst valve means; means providing communication between said mainchamber and said first compartment, and-between said main chamber andsaid second compartment; a second valve means controlling thecommunication between said main chamber and said first compartment;means maintaining said second valve means normally closed; and meansaccenna :l feective @during ithe operation lof fsaid frst 'valve meansto iactuate fsaid `second Lvalve means.

23. :The combination rolf 'a ifrst ibody provided rwith .a mainchamber.; a second body provided with a :inst auxiliary chamber; a`third bod-y mounted intermediate said rst and `second bodies, fafnrliprovided with .a second :auxiliary aiharnber.; :means `:prot/.iiiimgcommunication V'with linterior e'of fsa'id :main rchaniber.; a firstdisc 'controlling Asaid communication.; Qa ystern extending from isaidldisc 'through .said second auxiliary ychamber :and .into said .irstauxiliary chamber; means mounted ein said '.irst "auxiliary chamber amdicoopcrable with .said fstem, maintaining said first disc normallylosed'.; .fa :diaphragm periphaeraly'mounted in said third body, and4dividing ,the :same :into :fi-rst iand `.second .compartmen' s; saiddiaphragm being .'.coupled at rthe :center thereof to said zstem; fmeansproviding communication ibetwe'ensaid .mainchamber and said iirstcompartment, and :between .said :main Ychazriber and isaid Vfsecrmrlcompartment; a second .disc controlling the .communication `between saidemain `chamber and said first compartment; means maintaining said second`disc :normally closed.; a ica-m :mounted :on stem; .and a @ushered:extending strom .said second `disc 'to a point :adjacent .said loam.;ysaid ycani engaging said mush-@rod :during l.the operation 'of saidfirst disc :toactuatefsai'desecond disc.

f4. flllhe combination .a .body provided with .main rand auxiliarychambers; means .providing communication smh :the .interior .of saidmain chamber; .a .first "valve .means controlling said communication;.means tmaintaining lsaid first valve fmeans tnornially closed; a'pi'essure-resnon vsive cnember :disposed .'said .auxiliary chamber, andrdividing the fsame .into :first .and second conv.- partments; saidpressure-responsive :member bein g coupled to .said `first val-ve means;means ,providing :communication between :said main chamber and said'.nrst compartment, and lbetween said main chamber and said .second'compartment; :afsecond valve .means controlling the communicationbetween .said main .chamber yand said rst compartment; .means providing:a :bypass tosaidmain chamber .of the `communication .between Asaid mainchamber .and said 'second compartment; :a third valve means controlling`said 1by-.pass.; vmeans maintaining said second i and third valve meansnormally closed; 'and `Ameans effective during the operation of saidlrstvalve .means #to ractuate said second .and .third valve means.

.5. .The combination of a lbody vl.provided with main Iand auxiliarychambers; means .providing communication with the interior :of `:said.main chamber; a first disc controlling said communication; .meansmaintaining said irst disc normally closed.; :a ypressure--responsiveimember .disposed 4in 'said auxiliary chamber, :and ldividing the same:into first Vand second compartments; ,said pressure-responsive .memberbeing coupled to :said .first `disc; means providing 'commu-nica- .tion:between :sai-cl .main chamber and said rst compartment, and ,between:said .main vchamber and vsaid `second compartment; a s-ec'ond 'disccontrolling vthe .communication between .said main chamber and saidfirst compartment; meansproviding a:by-passto said main kchamber of.thecomrnunication 'between said lmaincham- .ber and-said secondcompartment.; -a :thi .disc controlling .said bij-pass.; v:means'maintaining-said second yand :third discs normally aclos'ed'; a camcoupled .to :said rstrdisc; 'andav push-rodfcoupled fil) lto .saidfsecon rand hird discs, and extending Ktherefrom Jtofa point adjacentisaid fcam vsa'ilvcam engaging said rpush-rod Yiur-ing V-ihe 4'operationvof :said first :cl-isc to actuate said second fand third sdiscs.

16,'Ilhe combination Lof 'fa fbody 'provided `with mainand'Iauxiliary-^chambers`; a vnozzleextending .intcfsaitlbodyandlprov-i'ding c'ommunication'with lfthe ilnterior vof f'sai'd mainchamber; yfa first -disc cooper-able with -a seat on'the inner end yoflsaid nozzle "to control said communication; fm'eans maintaining saidfirst disc normally closed; la 'pressure-responsive 'member 4disposed insaid auxiliary `chamber, yand fdividing fthe same in'to first :andsecond compartments; sai'd pressureresponsive n1enibe1b'ei-ngcoupledfto'said rstdisc; means 'providing communication between 'a pointlocated .in said rn'a'in chamber adjacent said 'first fdisc and fsa'i'drseat, and said firstfcompartment, andbe'tween vsaid point -in 'saidmain-chamb`er1and lsaid second compartment; a second disccontrollingth'e communication-between said main cham-berend said irstcompartment; means providing :a by-'pass #to said main chamber of the:communication between Asaid fin-ain chamber land said 'secondcompartment; the main chamber end :of said by--pass "being -remotelylocated with respect 'to :said point adjacentsaid rst disc *and saidseat; a third disc controlling said Ilbil-pass; means maintaining saidsecond v'and third discs normally f closed; and means l'effectivel1:luring fthe operation :of said 'first Vdisc v.to actuate sai-iisecond and ythird discs.

7. The combination of a body provided with main and auxiliary chambers;`means)providing `communication with the *interior fof said mainchamber; a Ifirst val-ve means controlling 'said communication; meansmaintaining said *rst 4valve .means lnormally rclosed; apressure-responsive member 'disposed in 4said auxiliary chamber,and-dividing the same rnto rs't'andsecond comparliaments; :saidpressure-responsive"member being coupledfto said'fiirst valve means;means proyiding communication between Vsaid main charnber 'and lsaid-hrstcornpartment, and vbetween said main chamber `and said secondcompartment; means providing Fadditional communi-cation between saidmain chamber and'saidcs'econdcompartment; a f' second vvalve meanscontrol-ling the communication 'between 'said main chamber and saidiirst compartment; lmeans maintaining said second valve means lnormallyclosed; means adjustably -restricting the size of the y'additionalcommunication between -fsaid main nchamber 'and said second compartment;land means 'ei-lectivo during 'the operation of said rs't IValve meansto `actuate `said second Valve-means 3. The combination of a body'provided with main and auxiliary chambers; means .providingcommunication .with the 'interior ofsad main chamber; a .rst valve.means controlling said communication; means .maintaining 'said firstvalve .means .normallyclose z:a pressure-responsive member disposed insaid auxiliary chamber.. and y.dividing .the same into rst and 1secondcomparliaments; said Ypressureresponsive member lbeing coupled to -saidfirst vvalve means; means providing -icommunication .between said mainchamber `and .said first compartment, and 4loe-- .tween fsaid fmalin-chamber jand said second compartment; means providing additionalcommunicationbe'twe'en -said main 4chamber andsaid second compartment;"a second Valve v'means vcontrolling -the 4communication Y'between saidmain chamber and said first compartment; means maintaining said secondvalve means normally closed; a manually adjustable needle valverestricting the size of the additional communication between said mainchamber and said second compartment; and means effective during theoperation of said rst valve means to actuate said second valve means,

10 References Cited in the le of this patent UNITED STATES PATENTSNumber Name Date Ebeling June 12, 1917 Raymond Oct. 2,1928 Hopkins Mar.24, 1936 Campbell July 11, 1939 Tobin Feb. 3, 1942 McClure Mar. 28, 1950

